How to count?

Hello all, I have a stochastic signal, and I want to count how many of the samples are positive,and how many are negative. Any suggestions?

[Negar]

Here is my signal:

x1 = 2*(rand(1,N)>0.5)-1;

It is a binay stochastic signal with samples equal to either 1 or -1.

Thanks a lot..

Answer 1

[Robert Cumming]

To find how many equal -1

answer = length(find ( x1 == -1 ));

Answer 2

[Titus Edelhofer]

Hi Negar,

just count them

nPos = sum(x1==1)
nNeg = sum(x1==-1)

Titus

[Jan]

SUM is usually faster than LENGTH(FIND).

nNeg = numel(x1) - nPos